Accidents, illnesses, diseases and strokes reduce people's ability to execute simple motor tasks, such as walking, reaching, and standing. The number of individuals with motor control deficiencies has grown rapidly in recent years. Improvements in health care, emergency response, and increased medical knowledge has led to a higher survival rate. With an increasing population of injured persons, the cost of rehabilitation, hospital stay, and medical expenses will continually increase each year. Billions are spent every year treating patients; costs are associated with medical care received. Such injuries are financially devastating to the victims and families; psychological, emotional, and financial distresses usually accompany such injuries. Not included in medical costs are lost productivity and reduced quality of life.
Although affected individuals may experience a return of some function (due to the plasticity of the nervous system or limited neural regeneration), intensive therapy is usually required to help restore lost motor function. A major deficit affecting a majority of patients is the inability to ambulate normally.
Over the years, scientists have obtained a better understanding of the underpinnings and mechanisms of human motor control. Various rehabilitative techniques and training methods have been experimented with. One of the first methods involved locomotion training in animal experimentation. Due to the success of locomotion training in animals, it was later tested on human subjects. Locomotion training further evolved to include treadmill training techniques. Expanding upon treadmill training, repetitive motion therapy was introduced to better train patients, and continues in widespread use today.
During the beginning phases of repetitive motion therapy, two or three physical therapists are often required to provide assistance. Two therapists either sit or kneel beside the patient and manually move the limbs through patterns resembling normal physiological movement. Depending on the partial weight bearing apparatus utilized, a third therapist may be required for hip stabilization. Due to the difficulty of the work, training sessions may be limited to the physical endurance of the therapists, rather than that of the patient. Generally, training sessions last for 30 minutes a day, 4 or 5 days a week. Sessions can be limited by the costs of employing multiple therapists each day over the course of the training time. Costs multiply with each additional patient. Although patients receive quality therapy, the lack of a standardized method leads to variability in training. Effective repetitive motion therapy relies on reproducible flexion and extension of the hips and knees, and also, loading and unloading of the lower limbs. Variability in the training of subject will lead to differences in flexion and extension and loading and unloading across subjects.
Limitations of manual training by physical therapists can be summarized as follows: (a) it is a strenuous task for therapists; (b) physiological movement patterns are non repeatable; (c) patient training time is limited by the endurance levels of therapists; and (d) treatment is expensive compounded over time.
Researchers have also experimented with various mechanical/robotic assistive devices. There are limitations associated with using these devices as well. The mechanical/robotic systems are also very expensive and complex. Moreover, the position control approaches used to drive extremities have only limited ability to adapt as the subject's ability to generate independent motions improves. Although these devices achieve their goals for producing repeatable motion training, they can be expensive, immobile, and require expert supervision during use of the device.
An uncomplicated device is needed to provide assistance to patients during repetitive motion therapy because current techniques are strenuous for physical therapists and expensive in employing multiple therapists. Also, existing mechanical devices can be expensive, complicated, and immobile. An assistive device is desired to help reduce costs associated with repetitive motion training and expand therapy to a greater number of patients.
A need exists for a simple, inexpensive, assistive device to alleviate the workload of physical therapists and to increase the availability of therapy.